Warm-Up

Using the GCF to Reduce or Factor

Percent: Definition, Purpose & Use Mental Math With Percent

Class Work: Focus on Fractions

Today:December 10, 2014

Fraction, Decimal, & Percent Unit

Warm-Up:

1. Before working this problem, look at/analyze it, then describe your plan to solve based on what you see in this particular problem. Be specific, use complete sentences. Do not solve yet.

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1. -3n2 + 7nn

Because there is more than one term, I’m going to simplify

by factoring. I will cancel factors from the numerator &

denominator if I can

3. Which fraction must have more than two decimal places?Why??

A.) ¼ B.) 2/5 C.) 12/50 D.) 5/6 E.) None

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This is not a proportion, so I’ll have to multiply

each term by the LCD to eliminate the

denominators.

Then I’ll combine like terms and solve as usual.

2. Same directions for this problem:

2.𝐱+ 𝟑

𝟐+

𝐱+𝟐

𝟓=

𝟏 𝟑

𝟑 = 3𝟏𝟎

𝟐𝟏

Because six does not go evenly into 100.

Warm-Up:

5. 10m – 15n5

Simplify:

6. 20a6b5

35a2b3

7. 15x2 + 21x6

9__2(x – 1)

7. 4510x – 10

2 3

= ?_ 18

Warm-Up:

Khan

Review:

October? English: Decade, December?

A decimal is a fraction with a denominator that is also a place value.

Decimal: Latin decimalis, meaning tenths. Root is Latin decim, ten.

Decimals and fractions cannot be mixed in the same

number 𝟑.𝟓

𝟒

Percent: From the Latin per centum. Per: for each as in "One per student.” Centum: hundred Century, Cent, Centimeter, Centipede

Percent: Definition

100% = 100 = 1100

**Fractions, Decimals, & Percents are three different ways of expressing the same amount. All three show a single number based on the relationship (ratio) between two other numbers.

50% = 50 = 𝟏

𝟐= .5

100

5% = 05 = 1 = .05100 20

Fractions Decimals Percent

Since the % sign cannot be +, -, x, ÷; numbers expressed as percents must be changed to a decimal or fraction before any calculations can be made.

A. How to change a decimal to a percent:?

B. How to change a percent to a decimal:?

C. How to change a fraction to percent, or percent to fraction?

Move the decimal 2 places to the right and add the % sign.

Move the decimal 2 places to the left and drop the % sign.

To change a fraction to percent, or percent to fraction, the number must be changed to a decimal first.

Fractional Conversions:

Fraction Decimal Percent

0.5 50

0.33 33.3

0.25 25

0.20 20

0.16 16.7

0.1428571 14

0.125 12.5

0.11 11

0.09 9

Mental Math:Percent of a Number

A. 10% of $1.00 is .1, or (10 cents). To find 10%, simply move the decimal one place to the left.

To find 20% of any number, multiply by 2 and move the decimal one place to the left.

𝟏

𝟏𝟎

To find 20% of a number, you could multiply a number by 𝟏

𝟓

B. 20% is what fraction?𝟏

𝟓

.2

20% of 40 is….. 8

The easier way, though, is to multiply a number by the decimal form of 20%, which is....

Mental Math:Percent of a Number

Find 20% using mental math

Find 15% using mental math

1) 20

3)

42.1

1) 10

4) 1201) 10 3) 60

3) 60

4) 380

Find 5% using mental math 4) 1601)

10

3) 60

4) 125

2) 25

2) 20

2) 20

2) 3.5

Class Work: